Method for drilling a well

ABSTRACT

A method for drilling an oil or gas well or the like which does not utilize a conventional derrick and rig which requires several operators and extensive moving equipment and the like, but rather the drilling is carried out with a minimum of simplified equipment. The invention contemplates mounting a generally up and down travelling rotary table over a well bore site. It includes the step of suspending a drill string from the rotary table and holding the drill string therein against downward movement relative thereto, with the drill string having drill collars and a drill bit on the lower end thereof. The rotary table is simultaneously rotated and lowered to effect drilling of the well bore while flowing a drilling fluid through the drill string. Thereafter, rotation of the rotary table is terminated and the rotary table disengaged from the drill string while supporting the drill string at a point below the rotary table. The drill string is held against rotational and downward movement during this supporting step. An additional section of pipe is placed in the rotary table and held therein against rotational and downward movement relative thereto. The lower end of the additional section of pipe is connected with the drill string by lowering and rotating the rotary table. Thereafter, the drilling operation is resumed by rotating and lowering the rotary table. In certain instances, the drill string may be held against both up and down movement while being supported at the position below the rotary table and likewise may be supported against both up and down movements relative to the rotary table at certain times.

United States Patent 1 Ray [54] METHOD FOR DRILLING A WELL [75] Inventor: Jack 11. Ray, Houston, Tex.

[73] Assignee: Tenneco Oil Company, Houston,

Tex.

[22] Filed: Apr. 8, 1971 Appl. No.: 132,323

[52] US. Cl. ..175/57, 173/149, 173/164 [51] Int. Cl. ..E21b 7/00, E210 5/00, E210 1/00 [58] Field of Search ..175/52, 85, 57, 52; 173/147, 173/149, 164

[56] References Cited UNITED STATES PATENTS 3,158,213 11/1964 O'Neill et al. ..l75/85 3,613,804 10/1971 Jonsson ...173/l47 X 2,126,933 8/1938 Stone et al.... ..l73/l49 X 2,848,196 8/1958 Simmonds ..l75/52 3,131,776 5/1964 Kvello-Aune et a1... ...l73/149 3,158,212 11/1964 Fanshawe et a1. ..l75/85 Primary Examiner-David H. Brown Attorney-Eugene S. Coddou and Lee R. Larkin [5 7] ABSTRACT 11] 3,722,607 51 Mar. 27, 1973 which requires several operators and extensive moving equipment and the'like, but rather the drilling is carried out with a minimum of simplified equipment. The invention contemplates mounting a generally up and down travelling rotary table over a well bore site. It includes the step of suspending a drill string from the rotary table and holding the drill string therein against downward movement relative thereto, with the drill string having drill collars and a drill bit on the lower end thereof. The rotary table is simultaneously rotated and lowered to effect drilling of the well bore while flowing a drilling fluid through the drill string. Thereafter, rotation of the rotary table is terminated and the rotary table disengaged from the drill string while supporting the drill string at a point below the rotary table. The drill string is held against rotational and downward movement during this supporting step. An additional section of pipe is placed in the rotary table and held therein against rotational and downward movement relative thereto. The lower end of the additional section of pipe is connected with the drill string by lowering and rotating the rotary table. Thereafter, the drilling operation is resumed by rotating and lowering the rotary table. In certain instances, the drill string may be held against both up and down movement while being supported at the position below the rotary table and likewise may be supported against both up and down movements relative to the rotary table at certain times.

3 Claims, 3 Drawing Figures METHOD FOR DRILLING A WELL BACKGROUND 'OF THE INVENTION l. Field of the Invention The field of the invention is methods for drilling well bores.

2. Description of the Prior Art The use of rotary drilling equipment has been carried to a high state of the art. However, the methods of handling the drill string are cumbersome and complex.

SUMMARY OF THE INVENTION It is, therefore, an object of this invention to provide an improved method for drilling oil wells and the like. This invention includes the steps of mounting a generally up and down travelling rotary table over a well bore site, suspending a drill string from the rotary table and holding the drill string against downward movement relative thereto, said drill string having drilling collars and a bit on the lower end thereof; simultaneously rotating and lowering the rotary table to thereby effect drilling of the well bore by the drill string and bit while flowing a drilling fluid through the drill string. It also includes the steps of disengaging the rotary table from the drill string while supporting the drill string at a point below the rotary table against rotational and downward movement in the well bore; placing another section of pipe in the rotary table and holding that additional section therein against rotational and downward movement relative thereto; and connecting the lower end of the additional section of pipe with the drill string by lowering and rotating the rotary table. At that point the drilling of the well bore is resumed.

In addition to utilizing the weight of the drill string for downwardly directed drilling force, the rotary table grasping the drilling string may be forced downwardly to provide additional force for drilling. Further, the drill string may also be supported at a point on the rotary table such as to prevent upward movement of the drill string in the well bore when the rotary table is disconnected from the drill string.

The method may be carried out with an easily movable light-weight drilling apparatus which will avoid the problems of large crews by requiring for its operation a crew of only about two men.

BRIEF DESCRIPTION OF THE DRAWINGS The inventors preferred embodiment may be further understood by reference to the drawings, in which:

FIG. 1 is a side elevation view from the right of one embodiment of this invention.

FIG. 2 is a partial front elevation view of the stationary drill string clamps and the movable rotary table and rotatable clamps.

FIG. 3 is a partial sectional view of the drill string engaging clamps and actuating means for the clamps taken along line 3--3 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, one form of apparatus useful in carrying out the preferred embodiment of the invention includes a platform generally designated by the numeral 10. Mounted thereon for support of a section of drill pipe is an A-frame 11. A-frai'ne 11 is connected to platform 10 by means of a pivotal connection 13. A-frame 1 1 is raised and lowered about the pivot by a hydraulic cylinder 14. A-frame 11 is further stabilized by a guy line 15 extending from one comer of platform 10 to an upper portion of A-frame 11 and brace 19 joining hydraulic cylinder 14 and A-frame 1 1.

Mounted adjacent to A-frame 11 on platform 10 is a vertically movable rotary table unit for engaging a section of drill pipe in drill string 12, which unit is generally designated by the numeral 20.

Unit 20 includes a plurality of support cylinders 21 which enclose therein pistons (not shown) for moving rotary table 24 upward and downward relative to support cylinders 21. The pistons within support cylinders 21 are connected to rotary table 24 by a plurality of support rods 22. Suitable hydraulic fluid may be injected either above or below the pistons within cylinder 21 by one or the other of the hydraulic conduits 23, thereby driving rotary table 24 either up or down.

The lower portion of unit 20 is provided with a clamp assembly 25 which is neither vertically movable nor rotatable with respect to the well bore 30 and support cylinders 21. Clamp assembly 25, when engaged with drill string 12, prevents rotational and downward movement thereof with respect to well bore 60, and may also be operated to prevent upward movement of the drill string. Clamp assembly 25 includes a generally cylindrical annular body 27, mounted immovably with respect to support cylinders 21. Referring to FIG. 3, which represents the operative parts of both clamp assembly 25 and the rotatable clamp 40, clamp housing 27 is shown adjacent to a portion of drill string 12 and a clamp cylinder 28 mounted on clamp housing 27. Within clamp cylinder 28 is disposed a clamp piston 29 arranged for moving a plurality of slips 26 into and out of engagement with drill string 12 responsive to hydraulic pressure applied through pressure tubes (not shown). Piston 29 and slips 26 are connected for corresponding movement by a clamp piston rod 30 engaged with an annular slip retaining ring 31. Hydraulic pressure above piston 29 causes axial movement of piston 29 and piston rod 30, thereby moving the annular retaining ring 31 and associated slips 26 out of engagement with drill string 12. To engage drill string 12, hydraulic pressure is applied to cylinder 28 below piston 29, forcing piston rod 30, retaining ring 31 and slips 26 upward. As slips 26 are urged upward, they contact the inner shoulder 27a of clamp housing 27 and are forced radially inward into engagement with drill string 12.

Rotable clamp 40, associated with rotary table 24, is rotable and movable vertically with respect to the well bore 60, clamp assembly 25 and the lower portion of unit 20. FIG. 3 may be used to show a partial section of rotable clamp 40 as well as clamp assembly 25. Rotable clamp 40 includes a clamp housing 41, clamp cylinder 42, clamp piston rod 43, annular slip retaining ring 44 and slips 45, all functionally and structurally equivalent to the respective counterparts of immovable clamp assembly 25. Rotable clamp 40 is supported in rotary table 24 by means of bearing assembly 50, and rotary table 24 is rotated by any suitable drive means such as, for example, a conventional hydraulic motor.

During drilling operations, drilling fluid may be supplied to drill string 12 by means of a flexible mud conduit 16 rotably connected with drill string 12 by a swivel 17 which is vertically movable by a cable 18 and a winch 35. Swivel 17 remains fluidly connected to the uppermost section of drill string 12 as the drill string is lowered and rotated into the earth during drilling operations. The drilling apparatus may be provided with a second mud line 16a and a second swivel 17a in order to speed up the process of adding a section of pipe to the drill string.

While drilling is being carried on with one swivel connected to the uppermost section of drill string 12, second swivel 17a and mud line 16a may be connected to a joint of pipe to be subsequently raised into place by cable 18 and added to the drill string.

Sealingly engaged with well bore 60 and located on the lower portion of snubber unit 20 is a wellhead casing 70. Wellhead casing 70 receives drill string 12, hav ing conventional drill collars and a bit, and seals any pressure present within well bore 60 from the atmosphere. A sleeve seal 71, of the type commonly referred to in the art as a Hydril, or stripping-in sleeve, is supported at the upper most portion of wellhead casing 70. Sleeve seal 71 includes an elongated seal (not shown) which frictionally seals wellhead casing 70 against drill string 12 to prevent any pressure within well bore 60 from escaping to the atmosphere. Immediately below sleeve seal 71 in wellhead casing 70 are located two conventional blowout preventers which take the form of a blind ram preventer 72 and a bore ram preventer 73. Blind ram preventer 72 is actuated to seal well bore 60 from the atmosphere only if no pipe is in position within wellhead casing 70 when a sudden surge of high pressure gas is encountered within well bore 60. Bore ram preventer 73 seals similarly against such sudden high pressure surges when drill string 12 is in position within wellhead casing 70.

During drilling operations, rotary table 24 is elevated to its maximum vertical extension over the well bore site and a section of drill string 12 is engaged by rotable clamp 40 and held against rotation and downward movement relative thereto. Rotation of the rotable table 24 is begun. Rotary table 24 and drill string 12 are then lowered by operation support cylinders 21. As rotary table 24 approaches its lower limit of downward movement, rotation of the drill string is ceased and stationary clamp assembly 25 is engaged with drill string 12. Clamp assembly 25 holds the drill string against up and down movement and against rotational movement in the well bore. Rotable clamp is then disengaged from drill string 12 and rotary table 24 elevated again to its maximum vertical extension, at which time rota ble clamp 40 is re-engaged with drill string 12 and clamp assembly 25 is disengaged therefrom. Drilling operations are hen resumed by again rotating and lowering rotary table 24 and drill string 12.

As drill string 12 is lowered by the use of rotary table 24, drill string 12 passes into wellhead casing 70 through sleeve seal 71 and past blind ram preventer 72 and bore ram preventer 73. Both ram preventers are in the retracted attitude, thus leaving space within wellhead casing 70 for passage of drill string 12 therethrough and into the earth. Sleeve seal 71 is radially retracted sufficiently to allow passage of the drill bit (not shown) to pass through the upper portion of wellhead casing 70. When a pressure is present in well bore 60, sleeve seal 71 may be radially distended to sealingly engage drill string 12 to prevent passage of pressure from well bore to the atmosphere.

Sleeve seal 71 is mounted within wellhead casing to be retracted radially sufiiciently to allow passage of drill collars (not shown) and casing pipe (not shown) into well bore 60. It is to be understood that drill collars may be used in this embodiment of the invention to exert additional downward pressure for drilling. Additional downward pressure on the drill bit may be applied by operation of support cylinder 21 and associated pistons. Reinforced drill pipe which will accommodate high compressive loads may be used when drilling pressure is derived from the descending rotary table alone.

Both rotable clamp 40 and clamp assembly 25 provide positive control and support of drill string 12. Both clamps 40 and 25 may be operated to hold drill string 12 against both up and down movement relative to the respective clamps, and prevent the drill string from blowing out of the hole against pressure encountered in the well. Additionally, positive control of the drilling rate may be maintained by rotable clamp 40 holding drill string 12 against both up and down movement thereto. Further, clamps 40 and 25 hold the drill string against rotational relative movement thereto, which permits their use in makeup and breakout operations, in the place of conventional tools.

When drill string 12 has been drilled into the earth, second swivel 17a, connected to an associated joint of drill pipe, is raised by cable 18 to position over snubber unit 20. Rotary table 24 is then raised to place the next section of drill pipe in rotary table 24 while drill string 12 is held against any up and down and rotational movement by clamp assembly 25. The pin end of the new joint of pipe is then aligned with the box end of drill string 12 and engaged by rotable clamp 40. The new joint of pipe is then rotated by rotary table 24 and screwed into the box end of drill string 12. Drilling operations are then resumed.

When it becomes necessary to pull the drill string from the hole, the operation of inserting a new joint of drill pipe is reversed. The rotation of rotary table 24 is ceased and drill string 12 is elevated to the height of maximum vertical extension of rotary table 24. Clamp assembly 25 is operated to engage the drill string, holding the drill string against up and down and rotational movement with respect to well bore 60. Rotary clamp 40 is then disengaged, and rotary table 24 lowered to its point of minimum elevation and re-engaged with drill string 12. This operation is continued until the connection between the two joints of drill string 12 is between the rotary table 24 and clamp assembly 25. At that point, both the clamp assembly 25 and rotary clamp 40 are engaged below and above the connection point,

respectively, and the rotary table 24 is counter-rotated to disengage the top section of drill pipe. The section is then removed from rotary table 24 and the operation continued until all of drill string 12 has been removed from well bore 30.

The foregoing method is particularly adapted for remote drilling operations where it is desirable to drill an oil or gas well or the like to a depth of 7000 or 8000 feet, for example. The method can be used with conventional drill pipe, drill collars and drill bits. The use of the rotary table 24 and clamp assembly 25 eliminates the need for conventional makeup and breakout tools to a large extent. The method of this invention can be carried out without the use of the conventional drilling derrick which is normally used to suspend the weight of the drill string during the drilling operation and, thereby, eliminates the need for a travelling block to support the drill string. Since the method of this invention can be carried out with light equipment, there is thus eliminated the need to have a large sub-structure to support the drilling structure. While the device described for carrying out the invention in the foregoing specification includes means for holding the drill string against upward movement thereof when pressure conditions prevail at the wellhead, it is normally anticipated that well conditions will be maintained such that drilling operations can be carried out without the necessity for snubbing the drill string into the well bore except in special circumstances, in which event applicants method can be used in a manner to overcome such problems, as is described above.

Thus it can be seen that an efficient and economic method for drilling a well with a reduced crew has been shown. Further modifications and alternative embodiments of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the manner of carrying out the invention. It is to be understood that the form of the invention herewith shown and described is to be taken as the presently preferred embodiment. Various changes may be made in the shape, size and arrangement of parts. For example, equivalent elements or materials may be substituted for those illustrated and described herein, parts may be reversed, and certain features of the invention may be utilized independently of the use of other features, all as would be apparent to one skilled in the art after having the benefit of this description of the invention.

What is claimed is:

1. In a method of drilling a wellbore into a hydrocarbon bearing formation or the like, the combination of steps comprising:

mounting a plurality of generally vertically extending hydraulic piston and cylinder assemblies over a wellbore site;

supporting a rotary table on the upper ends of said hydraulic piston and cylinder assemblies, whereby extension and retraction of said assemblies causes raising and lowering of said rotary table;

attaching a first plurality of hydraulically actuated pipe gripping elements to said rotary table for rotation therewith;

supporting another plurality of hydraulically actuated pipe gripping elements axially below said first plurality of pipe gripping elements, said second plurality of elements being generally held against axial and rotational movement when in the engaged position with said drill string;

placing the initial portion of the drill string in said rotary table;

actuating said first plurality of pipe gripping elements into engagement with said drill string, whereby said drill string is suspended by said rotary table and held against axial and rotary movement relative to said rotary table;

connecting a rotary swivel to the upper end of said drill string,

rotating said rotary table to thereby effect rotation of said drill string;

lowering said drill string during said rotation by operating said hydraulic piston and cylinder assemblies, to thereby efiect drilling of said wellbore by said drill string;

flowing a drilling fluid through said swivel and drill string during rotation of said drill string;

terminating rotation of said rotary table and flowing of said drilling fluid,

disconnecting said swivel from said drill string;

actuating said second plurality of gripping elements, whereby said drill string is held against rotational and downward movement in said wellbore;

deactuating said first plurality of pipe gripping elements, whereby said rotary table is disengaged from said drill string,

raising said rotary table and placing an additional section of drill pipe in said rotary table;

actuating said first plurality of gripping elements, whereby said additional section of drill pipe is held in said rotary table against rotational and downward movement relative thereto;

lowering and rotating said rotary table with said additional section of drill pipe held therein to thereby make up said additional section of drill pipe with the upper end of said drill string;

deactuating said second plurality of said pipe engaging elements, whereby said drill string is supported by said rotary table;

reconnecting said swivel to the upper end of said drill string and resuming flow of drilling fluid therethrough;

and resuming rotation and lowering of said rotary table, to thereby resume said drilling operation.

2. The invention as claimed in claim 1 wherein said drill string is lowered in said wellbore by the steps of:

terminating rotation of said drill string;

actuating said second plurality of gripping elements,

whereby said drill string is supported thereby;

deactuating said first plurality of gripping elements, whereby said rotary table is disengaged from said drill string;

raising said rotary table by extending said hydraulic piston and cylinder assemblies;

actuating said first plurality of gripping elements and then deactuating said second plurality of gripping elements whereby said drill string is again supported by said rotary table;

and resuming said rotation and lowering of said rotary table to thereby resume said drilling operation.

3. The invention as claimed in claim 1 including:

second section;

e. removing said uncoupled section of drill pipe from said rotary table;

f. lowering said rotary table and actuating said first plurality of gripping elements into engagement with said drill string;

g. deactuating said second plurality of gripping elements from engagement with said drill stem;

h. and repeating said steps (b) through (g) until said drill string is removed from said wellbore. 

1. In a method of drilling a wellbore into a hydrocarbon bearing formation or the like, the combination of steps comprising: mounting a plurality of generally vertically extending hydraulic piston and cylinder assemblies over a wellbore site; supporting a rotary table on the upper ends of said hydraulic piston and cylinder assemblies, whereby extension and retraction of said assemblies causes raising and lowering of said rotary table; attaching a first plurality of hydraulically actuated pipe gripping elements to said rotary table for rotation therewith; supporting another plurality of hydraulically actuated pipe gripping elements axially below said first plurality of pipe gripping elements, said second plurality of elements being generally held against axial and rotational movement when in the engaged position with said drill string; placing the initial portion of the drill string in said rotary table; actuating said first plurality of pipe gripping elements into engagement with said drill string, whereby said drill string is suspended by said rotary table and held against axial and rotary movement relative to said rotary table; connecting a rotary swivel to the upper end of said drill string, rotating said rotary table to thereby effect rotation of said drill string; lowering said drill string during said rotation by operating said hydraulic piston and cylinder assemblies, to thereby effect drilling of said wellbore by said drill string; flowing a drilling fluid through said swivel and drill string during rotation of said drill string; terminating rotation of said rotary table and flowing of said drilling fluid, discOnnecting said swivel from said drill string; actuating said second plurality of gripping elements, whereby said drill string is held against rotational and downward movement in said wellbore; deactuating said first plurality of pipe gripping elements, whereby said rotary table is disengaged from said drill string, raising said rotary table and placing an additional section of drill pipe in said rotary table; actuating said first plurality of gripping elements, whereby said additional section of drill pipe is held in said rotary table against rotational and downward movement relative thereto; lowering and rotating said rotary table with said additional section of drill pipe held therein to thereby make up said additional section of drill pipe with the upper end of said drill string; deactuating said second plurality of said pipe engaging elements, whereby said drill string is supported by said rotary table; reconnecting said swivel to the upper end of said drill string and resuming flow of drilling fluid therethrough; and resuming rotation and lowering of said rotary table, to thereby resume said drilling operation.
 2. The invention as claimed in claim 1 wherein said drill string is lowered in said wellbore by the steps of: terminating rotation of said drill string; actuating said second plurality of gripping elements, whereby said drill string is supported thereby; deactuating said first plurality of gripping elements, whereby said rotary table is disengaged from said drill string; raising said rotary table by extending said hydraulic piston and cylinder assemblies; actuating said first plurality of gripping elements and then deactuating said second plurality of gripping elements whereby said drill string is again supported by said rotary table; and resuming said rotation and lowering of said rotary table to thereby resume said drilling operation.
 3. The invention as claimed in claim 1 including: a. terminating rotation of said rotary table; b. raising said rotary table while said drill string is supported thereby until the second section of drill pipe immediately below the first top section is adjacent said second plurality of gripping elements; c. actuating said second plurality of gripping elements into engagement with said second section of drill pipe, whereby said second section is held against rotation and said drill string is supported thereby; d. counter-rotating said rotary table to thereby unthread said top section of drill pipe from said second section; e. removing said uncoupled section of drill pipe from said rotary table; f. lowering said rotary table and actuating said first plurality of gripping elements into engagement with said drill string; g. deactuating said second plurality of gripping elements from engagement with said drill stem; h. and repeating said steps (b) through (g) until said drill string is removed from said wellbore. 